Wed·Jul 10, 2019Wednesday·July 10, 2019

1. 01*

   A Projective Phase Space Generator for Hadronic Vector Boson Plus One Jet Production

   Tinghua Chen🇺🇸 · Terrance M. Figy🇺🇸 · Walter T. Giele🇺🇸

   In this paper we use our previously developed projective phase space generator for the calculation of the hadronic production of a vector boson with one additional jet at Next-to-Leading Order. The projective phase space generator allows us to make physical predictions in novel ways, speeding up both evaluation time and attainable accuracy. For the numerical evaluation we explore a computational model which combines the use of both multi-threading and distributed resources through the use of grid or cloud computing without depending on local institutional computer availability. The projective phase space method is well suited for this approach and gives through the use of cloud computing instant access to a large pool of resources.

   hep-ph1 citation
2. 02*

   Decay modes of the scalar exotic meson $T_{bs;\overline{u}\overline{d}}^{-}$

   S. S. Agaev🇦🇿 · K. Azizi🇮🇷 · H. Sundu🇹🇷

   We investigate the semileptonic decay of the scalar tetraquark $T_{bs;\overline{u}\overline{d}}^{-}$ to final state $T_{cs;\overline{u}\overline{d}}^{0}l{\overline{\nu }}_l$, which proceeds due to the weak transition $b\to cl{\overline{\nu }}_l$. For these purposes, we calculate the spectroscopic parameters of the final-state scalar tetraquark $T_{cs;\overline{u}\overline{d}}^0$. In calculations we use the QCD sum rule method by taking into account the quark, gluon, and mixed condensates up to dimension 10. The mass of the $T_{cs;\overline{u}\overline{d}}^0$ obtained in the present work $(2878\pm 128)\mathrm{MeV}$ indicates that it is unstable against the strong interactions, and can decay to the mesons $D^0{\overline{K}}^0$ and $D^{+}{K}^{-}$. Partial widths of these $S$-wave modes as well as the full width of the tetraquark $T_{cs;\overline{u}\overline{d}}^0$ are found by means of the QCD light-cone sum rule method and technical tools of the soft-meson approximation. The partial widths of the main semileptonic processes $T_{bs;\overline{u}\overline{d}}^{-}\to T_{cs;\overline{u}\overline{d}}^{0}l{\overline{\nu }}_l$, $l=e,\mu$, and $\tau$ are computed by employing the weak form factors $G_1(q^2)$ and $G_2(q^2)$, which are extracted from the QCD three-point sum rules. We also trace back the weak transformations of the stable tetraquark $T_{bb;\overline{u}\overline{d}}^{-}$ to conventional mesons. The obtained results for the full width ${\Gamma }_{\mathrm{full}}=(3.28\pm 0.60)\times 10^{-10}\mathrm{MeV}$ and mean lifetime $\tau =2.01_{-0.31}^{+0.44}\mathrm{ps}$ of $T_{bs;\overline{u}\overline{d}}^{-}$, as well as predictions for decay channels of the tetraquark $T_{bb;\overline{u}\overline{d}}^{-}$ can be used in experimental studies of these exotic states. \end{abstract}

   hep-phhep-exhep-latPRD(2019)·14 citations
3. 03*

   Predictions for the neutrino parameters in the minimal model extended by linear combination of U(1)${}_{L_e-L_{\mu }}$, U(1)${}_{L_{\mu }-L_{\tau }}$ and U(1)${}_{B-L}$ gauge symmetries

   Kento Asai🇯🇵

   We study the minimal extensions of the Standard Model by a linear combination of U(1)${}_{L_e-L_{\mu }}$, U(1)${}_{L_{\mu }-L_{\tau }}$ and U(1)${}_{B-L}$ gauge symmetries, where three right-handed neutrinos and one U(1)-breaking SU(2)${}_L$ singlet or doublet scalar are introduced. Because of the dependence on the lepton flavor, the structures of both Dirac and Majorana mass matrices of neutrinos are restricted. In particular, the two-zero minor and texture structures in the mass matrix for the active neutrinos are interesting. Analyzing these structures, we obtain uniquely all the neutrino parameters, namely the Dirac CP phase $\delta$, the Majorana CP phases ${\alpha }_{2,3}$ and the mass eigenvalues of the light neutrinos $m_i$ as functions of the neutrino mixing angles ${\theta }_{12}$, ${\theta }_{23}$, and ${\theta }_{13}$, and the squared mass differences $\Delta m_{21}^2$ and $\Delta m_{31}^2$. In 7 minimal models which are consistent with the recent neutrino oscillation data, we also obtain the predictions for the sum of the neutrino masses ${\Sigma }_i{m}_i$ and the effective Majorana neutrino mass $⟨m_{\beta \beta }⟩$ and compare them with the current experimental limits. In addition, we also discuss the implication of our results for leptogenesis.

   hep-phhep-exEPJC(2020)·49 citations
4. 04*

   Studies of the resonance components in the $B_s$ decays into charmonia plus kaon pair

   Zhou Rui🇨🇳 · Ya Li🇨🇳 · Hong Li🇨🇳

   In this work, the decays of $B_s$ mesons to a charmonium state and a $K^{+}{K}^{-}$ pair are carefully investigated in the perturbative QCD approach. Following the latest fit from the LHCb experiment, we restrict ourselves to the case where the produced $K^{+}{K}^{-}$ pair interact in isospin zero $S$, $P$, and $D$ wave resonances in the kinematically allowed mass window. Besides the dominant contributions of the $\varphi (1020)$ resonance in the $P$-wave and $f_2^{\prime }(1525)$ in the $D$-wave, other resonant structures in the high mass region as well as the $S$-wave components are also included. The invariant mass spectra for most of the resonances in the $B_s\to J/\psi K^{+}{K}^{-}$ decay are well reproduced. The obtained three-body decay branching ratios can reach the order of $10^{-4}$, which seem to be accessible in the near future experiments. The associated polarization fractions of those vector-vector and vector-tensor modes are also predicted, which are compared with the existing data from LHCb Collaboration.

   hep-phEPJC(2019)·22 citations
5. 05*

   Ultra-light scalar saving the 3+1 neutrino scheme from the cosmological bounds

   Yasaman Farzan🇮🇷

   The LSND and MiniBooNE results as well as the reactor and Gallium anomalies seem to indicate the presence of a sterile neutrino with a mass of $\sim 1$ eV mixed with active neutrinos. Such sterile neutrino can be produced in the early universe before the neutrino decoupling, leading to a contribution to the effective number of neutrinos ($N_{eff}$) as well as to a contribution to the sum of neutrino masses which are in tension with cosmological observations. We propose a scenario to relax this tension by a Yukawa coupling of the sterile neutrinos to ultra-light scalar particles which contribute to the dark matter in the background. The coupling induces an effective mass for ${\nu }_s$ which prevents its production in the early universe. We discuss the implications for the upcoming KATRIN experiment and future relic neutrino search experiments such as PTOLEMY. We also briefly comment on certain non-renormalizable forms of interaction between ${\nu }_s$ and the scalar and their consequences for the ${\nu }_s$ production in the early universe.

   hep-phPLB(2019)·50 citations
6. 06*

   On the future of Higgs, electroweak and diboson measurements at lepton colliders

   Jorge de Blas🇮🇹 · Gauthier Durieux🇩🇪 · Christophe Grojean🇩🇪 · Jiayin Gu🇩🇪 · Ayan Paul🇩🇪

   LEP precision on electroweak measurements was sufficient not to hamper the extraction of Higgs couplings at the LHC. But the foreseen permille-level Higgs measurements at future lepton colliders might suffer from parametric electroweak uncertainties in the absence of a dedicated electroweak program. We perform a joint, complete and consistent effective-field-theory analysis of Higgs and electroweak processes. The full electroweak-sector dependence of the $e^{+}{e}^{-}\to WW$ production process is notably accounted for, using statistically optimal observables. Up-to-date HL-LHC projections are combined with CEPC, FCC-ee, ILC and CLIC ones. For circular colliders, our results demonstrate the importance of a new $Z$-pole program for the robust extraction of Higgs couplings. At linear colliders, we show how exploiting multiple polarizations and centre-of-mass energies is crucial to mitigate contaminations from electroweak parameter uncertainties on the Higgs physics program. We also investigate the potential of alternative electroweak measurements to compensate for the lack of direct $Z$-pole run, considering for instance radiative return to these energies. Conversely, we find that Higgs measurements at linear colliders could improve our knowledge of the $Z$ couplings to electrons.

   hep-phhep-exJHEP(2019)·127 citations
7. 07*

   Dark Matter Energy Deposition and Production from the Table-Top to the Cosmos

   Hongwan Liu🇺🇸

   The discovery of nongravitational interactions between dark matter and the Standard Model would be an important step in unraveling the nature of dark matter. If such an interaction exists, it would have profound implications on how dark matter is produced in both the early universe and in collider experiments. In addition, it would also allow dark matter to deposit energy into Standard Model particles in unexpected ways. This thesis details some recent progress made in understanding these implications, including (i) a new freezeout mechanism for thermal dark matter dominated by a 3-to-2 process within a vector portal dark sector model; (ii) a study of how the existence of dark sector bound states can influence collider, direct and indirect searches for dark matter; (iii) a new axion dark matter interferometric search using a cavity that is sensitive to the axion-induced rotation of linearly polarized light; (iv) a definitive assessment of the potential contribution of dark matter annihilation and decay to cosmic reionization; (v) new constraints on dark matter annihilation rates and decay lifetimes from 21-cm cosmology, and (vi) a new numerical code, DarkHistory, which significantly improves the computation of the ionization and thermal histories of the universe in the presence of exotic sources of energy injection. These novel ideas span length scales ranging from table-top experiments to the entire cosmos, and represent just a few of the myriad of ways in which dark matter may yet surprise us.

   hep-phastro-ph.CO1 citation
8. 08*

   The Singlet Extended Standard Model in the Context of Split Supersymmetry

   Martin Gabelmann🇩🇪 · Margarete M. Mühlleitner🇩🇪 · Florian Staub🇩🇪

   We consider a low-energy effective theory of the next-to-minimal supersymmetric Standard Model by decoupling all scalar states except one Higgs doublet and the complex gauge singlet. The mass spectrum of the resulting singlet-extended Standard Model is calculated from two different perspectives: 1) using a matching of the scalar sectors at next-to-leading order; 2) using the simplified-model approach of calculating the masses in the effective theory at fixed order at the weak scale ignoring any connection to the full theory. Significant deviations between the two methods are found not only in the scalar sector, but also properties of the additional fermions can be very different. Thus, only a small part of the parameter space of the simplified model can be embedded in a well motivated SUSY framework.

   hep-phPRD(2019)·9 citations
9. 09*

   Gravity-mediated Scalar Dark Matter in Warped Extra-Dimensions

   Miguel G. Folgado🇪🇸 · Andrea Donini🇪🇸 · Nuria Rius🇪🇸

   We revisit the case of scalar dark matter interacting just gravitationally with the Standard Model (SM) particles in an extra-dimensional Randall-Sundrum scenario. We assume that both, the dark matter and the Standard Model, are localized in the TeV brane and only interact via gravitational mediators, namely the graviton Kaluza-Klein modes and the radion. We analyze in detail the dark matter annihilation channel into two on-shell KK-gravitons, and contrary to previous studies which overlooked this process, we find that it is possible to obtain the correct relic abundance for dark matter masses in the range [1, 10] TeV even after taking into account the strong bounds from LHC Run II. We also consider the impact of the radion contribution (virtual exchange leading to SM final states as well as on-shell production), which does not significantly change our results. Quite interestingly, a sizeable part of the currently allowed parameter space could be tested by LHC Run III and by the High-Luminosity LHC.

   hep-phastro-ph.HEJHEP(2020)·38 citations
10. 10*

    Two-Loop $Z_4$ Dirac Neutrino Masses and Mixing, with Self-Interacting Dark Matter

    Ernest Ma (UC Riverside)🇺🇸

    Choosing how gauge $U(1{)}_{\chi }$ breaks in the context of $SO(10)\to SU(5)\times U(1{)}_{\chi }$, $Z_4$ lepton number may be obtained which maintains neutrinos as Dirac fermions. Choosing $\Delta (27)$ as the family symmetry of leptons, tree-level Dirac neutrino masses may be forbidden. Choosing a specific set of self-interacting dark-matter particles, Dirac neutrino masses and mixing may then be generated in two loops. This framework allows the realization of cobimaximal neutrino mixing, i.e. ${\theta }_{13}\ne 0$, ${\theta }_{23}=\pi /4$, ${\delta }_{CP}=\pm \pi /2$, as well as the desirable feature that the light scalar mediator of dark-matter interactions decays only to neutrinos, thereby not disrupting the cosmic microwave background (CMB).

    hep-phNPB(2019)·39 citations
11. 11*

    Seed and vacuum pair production in strong laser field

    Huayu Hu🇨🇳

    Researches on the electron-positron pair production in the presence of the intense laser field are reviewed, motivated by the theoretical importance of the nonperturbative QED problem and the worldwide development of the strong laser facilities. According to distinct experimental requirements and theoretical methods, two types of pair production are elaborated, which are respectively the pair production in the combination of a seed particle and the strong laser, and vacuum pair production without a seed particle. The origin of the nonperturbative problem caused by the strong field is analyzed. The main ideas, realization, achievements, validity, challenges and bottleneck problems of the nonperturbative methods developed for each type of the pair production problem are discussed.

    ↳ physics.atom-phhep-phphysics.opticsphysics.plasm-phContemp.Phys.(2020)·9 citations
12. 12*

    An analytic solution for the equal-mass banana graph

    Johannes Broedel🇩🇪 · Claude Duhr🇨🇭 · Falko Dulat🇺🇸 · Robin Marzucca🇧🇪 · Brenda Penante🇨🇭 · Lorenzo Tancredi🇨🇭

    We present fully analytic results for all master integrals for the three-loop banana graph with four equal and non-zero masses. The results are remarkably simple and all integrals are expressed as linear combinations of iterated integrals of modular forms of uniform weight for the same congruence subgroup as for the two-loop equal-mass sunrise graph. We also show how to write the results in terms of elliptic polylogarithms evaluated at rational points.

    ↳ hep-thhep-phJHEP(2019)·102 citations
13. 13*

    Damping of density oscillations in neutrino-transparent nuclear matter

    Mark G. Alford🇺🇸 · Steven P. Harris🇺🇸

    We calculate the bulk-viscous dissipation time for adiabatic density oscillations in nuclear matter at densities of 1-7 times nuclear saturation density and at temperatures ranging from 1 MeV, where corrections to previous low-temperature calculations become important, up to 10 MeV, where the assumption of neutrino transparency is no longer valid. Under these conditions, which are expected to occur in neutron star mergers, damping of density oscillations arises from beta equilibration via weak interactions. We find that for 1 kHz oscillations the shortest dissipation times are in the 5 to 20 ms range, depending on the equation of state, which means that bulk viscous damping could affect the dynamics of a neutron star merger. For higher frequencies the dissipation time can be even shorter.

    ↳ nucl-thastro-ph.HEgr-qchep-phPRC(2019)·82 citations
14. 14*

    Scaling properties of direct photon yields in heavy ion collisions

    Vladimir Khachatryan🇺🇸 · Michal Praszalowicz🇵🇱

    A recent analysis from the PHENIX collaboration of available direct photon measurement results in collisions of various systems such as Au+Au, Cu+Cu, and Pb+Pb, at different beam energies ranging from 39 to 2760 GeV, has shown a universal, within experimental uncertainties, $multiplicity$ scaling, in which direct photon $p_T$-spectra for transverse momenta up to 2 GeV/$c$ are scaled with charged hadron pseudorapidity density at midrapidity raised to power $\alpha =1.25$. On the other hand, those direct photon $p_T$-spectra also exhibit $geometrical$ scaling in the similar $p_T$ range. Assuming power-law dependence of the scaled photon spectra for both scaling laws, we formulate two independent conditions for the power $\alpha$, which overshoot experimental data by $\sim 10\%$ on average. We discuss possible sources that might improve this estimate.

    ↳ nucl-thhep-phEPJC(2020)·12 citations
15. 15*

    Parton-Hadron-Quantum-Molecular Dynamics (PHQMD) -- A Novel Microscopic N-Body Transport Approach for Heavy-Ion Collisions, Dynamical Cluster Formation and Hypernuclei Production

    J. Aichelin🇫🇷 · E. Bratkovskaya🇩🇪 · A. Le Fevre🇩🇪 · V. Kireyeu🇷🇺 · V. Kolesnikov🇷🇺 · Y. Leifels🇩🇪 · V. Voronyuk🇷🇺 · G. Coci🇩🇪

    Cluster and hypernuclei production in heavy-ion collisions is presently under active experimental and theoretical investigation. Since clusters are weekly bound objects, their production is very sensitive to the dynamical evolution of the system and its interactions. The theoretical description of cluster formation is related to the n-body problem. Here we present the novel n-body dynamical transport approach PHQMD (Parton-Hadron-Quantum-Molecular Dynamics) which is designed to provide a microscopic description of nuclear cluster and hypernucleus formation as well as of general particle production in heavy-ion reactions at relativistic energies. In difference to the coalescence or statistical models, often used for the cluster formation, in PHQMD clusters are formed dynamically due to the interactions between baryons described on a basis of Quantum Molecular Dynamics (QMD)which allows to propagate the n-body Wigner density and n-body correlations in phase-space, essential for the cluster formation. The clusters are identified by the MST (Minimum Spanning Tree) or the SACA ('Simulated Annealing Cluster Algorithm') algorithm which finds the most bound configuration of nucleons and clusters. Collisions among hadrons as well as Quark-Gluon-Plasma formation and parton dynamics in PHQMD are treated in the same way as in the established PHSD (Parton-Hadron-String Dynamics)transport approach. In order to verify our approach with respect to the general dynamics we present here the first PHQMD results for general 'bulk' observables such as rapidity distributions and transverse mass spectra for hadrons ($\pi ,K,\bar{K},p,\bar{p},\Lambda ,\bar{\Lambda }$) from SIS to RHIC energies. We find a good description of the 'bulk' dynamics which allows us to proceed with the results on cluster production, including hypernuclei.

    ↳ nucl-thhep-phPRC(2020)·132 citations
16. 16*

    Effect of anomalous magnetic moment of quarks on the phase structure and mesonic properties in the NJL model

    Nilanjan Chaudhuri🇮🇳 · Snigdha Ghosh🇮🇳 · Sourav Sarkar🇮🇳 · Pradip Roy🇮🇳

    Employing a field dependent three-momentum cut-off regularization technique, we study the phase structure and mesonic masses using the $2$-flavour Nambu-Jona Lasinio model at finite temperature and density in presence of arbitrary external magnetic field. This approach is then applied to incorporate the effects of the anomalous magnetic moment(AMM) of quarks on constituent quark mass and thermodynamic observables as a function of temperature/baryonic density. The critical temperature for transition from chiral symmetry broken to the restored phase is observed to decrease with the external magnetic field, which can be classified as inverse magnetic catalysis, while an opposite behaviour is realized in the case of a vanishing magnetic moment, implying magnetic catalysis. These essential features are also reflected in the phase diagram. Furthermore, the properties of the low lying scalar and neutral pseudoscalar mesons are also studied in presence of a hot and dense magnetized medium including AMM of the quarks using random phase approximation. For non-zero values of magnetic field, we notice a sudden jump in the mass of the Goldstone mode at and above the Mott transition temperature which is found to decrease substantially with the increase in magnetic field when the AMM of the quarks are taken into consideration.

    ↳ nucl-thhep-phPRD(2019)·67 citations
17. 17*

    Uncertainty quantification and falsification of Chiral Nuclear Potentials

    Rodrigo Navarro Perez🇺🇸 · Enrique Ruiz Arriola🇪🇸

    Are chiral theories at present describing experimental NN scattering data satisfactorily ?. Will the chiral approach offer a framework where fitting and selecting the existing np and pp data can be done without theoretical bias ?. While predictive power in theoretical nuclear physics has been a major concern in the study of nuclear structure and reactions, the Effective Field Theory (EFT) based on chiral expansions has emerged after Weinberg as a model independent hierarchy for many body forces and much progress has been achieved over the last decades. We review some of the issues involved which point to being close to the solution, but also that work remains still to be done to validate the theory. We analyze several examples including zero energy NN scattering and perturbative counterterm -- free peripheral scattering where one would expect these methods to work best and unveil relevant systematic discrepancies when a fair comparison to the Granada-2013 NN-database and partial wave analysis (PWA) based on coarse graining the interaction is undertaken.

    ↳ nucl-thhep-ph2 citations
18. 18*

    Weak field limit of higher dimensional massive Brans-Dicke gravity: Observational constraints

    Ozgur Akarsu🇹🇷 · Alexey Chopovsky🇺🇦 · Valerii Shulga🇨🇳 · Ezgi Yalcinkaya🇹🇷 · Alexander Zhuk🇹🇷

    We consider higher-dimensional massive Brans-Dicke theory with Ricci-flat internal space. The background model is perturbed by a massive gravitating source which is pressureless in the external (our space) but has an arbitrary equation-of-state parameter $\Omega$ in the internal space. We obtain the exact solution of the system of linearized equations for the perturbations of the metric coefficients and scalar field. For a massless scalar field, relying on the fine-tuning between the Brans-Dicke parameter $\omega$ and $\Omega$, we demonstrate that (i) the model does not contradict gravitational tests relevant to the parameterized post-Newtonian parameter $\gamma$, and (ii) the scalar field is not ghost in the case of nonzero $|\Omega |\sim O(1)$ along with the natural value $|\omega |\sim O(1)$. In the general case of a massive scalar field, the metric coefficients acquire the Yukawa correction terms, where the Yukawa mass scale $m$ is defined by the mass of the scalar field. For the natural value $\omega \sim O(1)$, the inverse-square-law experiments impose the following restriction on the lower bound of the mass: $m\gtrsim 10^{-11}$GeV. The experimental constraints on $\gamma$ requires that $\Omega$ must be extremely close to $-1/2$.

    ↳ gr-qcastro-ph.COhep-phhep-thPRD(2020)·6 citations
19. 19*

    Lightening the Dark Matter from its Viscosity and Explanation of EDGES Anomaly

    Arvind Kumar Mishra🇮🇳

    We study the visible photon production from the viscous dissipation of the dark matter (DM) fluid. The visible photon production depends on the magnitude of the dark matter viscosity and becomes important at the late times. We argue that for sufficiently large dark matter viscosity, the number of the resonantly converted visible photons becomes large which populates the Rayleigh-Jeans (RJ) tails of the Cosmic Microwave Background (CMB) radiation. Consequently, these excess visible photons possibly can explain the reported EDGES anomaly in the 21 cm signal. Further, we explore the parameter space for which the 21 cm signal can provide the region to probe the dark radiation and the DM viscosity.

    ↳ astro-ph.COhep-phJCAP(2020)·4 citations
20. 20*

    Search for Lorentz Violation Using High-Energy Atmospheric Neutrinos In IceCube

    Carlos A. Argüelles🇺🇸

    High-energy atmospheric neutrinos observed by the IceCube Neutrino Observatory are extremely sensitive probes of Lorentz violation (LV). Here we report the result of analyzing two years of IceCube data in the search for LV. This analysis places some of the strongest constraints on LV when considering high-dimensional operators.

    ↳ hep-exhep-ph1 citation
21. 21*

    de Sitter Cosmology on an expanding bubble

    Souvik Banerjee🇸🇪 · Ulf Danielsson🇸🇪 · Giuseppe Dibitetto🇸🇪 · Suvendu Giri🇸🇪 · Marjorie Schillo🇸🇪

    Constructing an explicit compactification yielding a metastable de Sitter (dS) vacuum in a UV consistent string theory is an incredibly difficult open problem. Motivated by this issue, as well as the conjecture that all non-supersymmetric AdS vacua must decay, we discuss the alternative possibility of realizing an effective four-dimensional dS cosmology on a codimension-one bubble wall separating two AdS${}_5$ vacua. The construction further elaborates on the scenario of arXiv:1807.01570, where the aforementioned cosmology arises due to a non-perturbative decay and is embedded in a five-dimensional bulk in a time-dependent way. In this paper we discuss the relation between this scenario and the weak gravity conjecture and further develop the details of the four-dimensional cosmology. We provide a bulk interpretation for the dS temperature as the Unruh temperature experienced by an accelerated observer riding the bubble. A source of four-dimensional matter arises from a string cloud in the bulk, and we examine the consequences for the particle mass spectrum. Furthermore, we show how effective four-dimensional Einstein gravity on the bubble is obtained from the five-dimensional Gauss equation. We conclude by outlining some implications that this paradigm will have for holography, inflation, the standard model, and black holes.

    ↳ hep-thgr-qchep-phJHEP(2019)·59 citations
22. 22*

    Intergalactic Magnetic Fields from First-Order Phase Transitions

    John Ellis🇬🇧 · Malcolm Fairbairn🇬🇧 · Marek Lewicki🇬🇧 · Ville Vaskonen🇬🇧 · Alastair Wickens🇬🇧

    We study the generation of intergalactic magnetic fields in two models for first-order phase transitions in the early Universe that have been studied previously in connection with the generation of gravitational waves (GWs): the Standard Model supplemented by an $|H{|}^6$ operator (SM+$H^6$) and a classically scale-invariant model with an extra gauged U(1) $B-L$ symmetry (SM${}_{B-L}$). We consider contributions to magnetic fields generated by bubble collisions and by turbulence in the primordial plasma, and we consider the hypotheses that helicity is seeded in the gauge field or kinetically. We study the conditions under which the intergalactic magnetic fields generated may be larger than the lower bounds from blazar observations, and correlate them with the observability of GWs and possible collider signatures. In the SM+$H^6$ model bubble collisions alone cannot yield large enough magnetic fields, whereas turbulence may do so. In the SM${}_{B-L}$ model bubble collisions and turbulence may both yield magnetic fields above the blazar bound unless the B$-$L gauge boson is very heavy. In both models there may be observable GW and collider signatures if sufficiently large magnetic fields are generated.

    ↳ astro-ph.COhep-phJCAP(2019)·71 citations
23. 23*

    Target Neutrino Mass Precision for Determining the Neutrino Hierarchy

    Constance Mahony🇬🇧 · Boris Leistedt🇺🇸 · Hiranya V. Peiris🇬🇧 · Jonathan Braden🇬🇧 · Benjamin Joachimi🇬🇧 · Andreas Korn🇬🇧 · Linda Cremonesi🇬🇧 · Ryan Nichol🇬🇧

    Recent works combining neutrino oscillation and cosmological data to determine the neutrino hierarchy found a range of odds in favour of the normal hierarchy. These results arise from differing approaches to incorporating prior knowledge about neutrinos. We develop a hierarchy-agnostic prior and show that the hierarchy cannot be conclusively determined with current data. The determination of the hierarchy is limited by the neutrino mass scale ${\Sigma }_{\nu }$ measurement. We obtain a target precision of $\sigma ({\Sigma }_{\nu })=0.014$ eV, necessary for conclusively establishing the normal hierarchy with future data.

    ↳ astro-ph.COastro-ph.IMhep-phPRD(2020)·17 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.